The crest of the existing dam wall will be raised by 8.4 m to 542.1 m AHD. This will be achieved by placement of rockfill on the upstream and downstream sides of the embankment.
The existing morning glory spillway will be raised by 6.5 m. This will effectively entail a duplication of the exiting morning glory intake at the raised level. The existing access bridge and trash rack structure will be extended to cater for the increase in storage level. No changes are proposed to the existing morning glory spillway outlet channel.
The existing auxiliary spillway fuseplug will be modified to a two-bay design to enable a staged trigger of the fuseplug, at the 1 in 10,000 and 1 in 20,000 Annual Exceedance Probability (AEP) events.